| A | B |
|---|
| virus | A tiny particle that can reproduce only inside the cells of living things. |
| bacteria | A tiny one-celled organisms, some of whichcan cause diseases |
| cell | The basic unit of a living organism |
| cell membrane | A thin layer that makes up the outside of the cell and controls what enters and leaves it. |
| nucleus | The cell part that controls the cell's activities |
| cytoplasm | A jellylike material that fills most of a cell |
| cell wall | A stiff outer layer that helps keep plant cells firm. |
| chloroplast | The green cell part in plant cells that traps and uses light energy. |
| vascular plant | A plant with long tubes inside that carry food and water to all the parts of the plant. |
| egg cell | A cell that can join with a sperm cell to form a new individual |
